Controlled-rectifier systems

Claim 1

IN A THREE-PHASE RECTIFIER SYSTEM SUPPLIED FROM A THREE-PHASE A.C. POWER SUPPLY SOURCE FOR ENERGIZING AN INDUCTIVE DIRECT CURRENT LOAD, SAID SYSTEM HAVING A THREE-PHASE RECTIFIER BRIDGE NETWORK CONNECTED BETWEEN SAID SOURCE AND SAID LOAD AND SAID NETWORK HAVING A PLURALITYOF CONTROLLED-RECTIFIERS CONNECTED IN EACH OF THREE LIKE BRANCHES THEREOF TO AFFORD ADJUSTABLE ENERGIZATION OF THE LOAD; (A) MEANS FOR CONTROLLING FIRING OF THE CONTROLLEDRECTIFIERS IN THE THREE BRANCHES IN SEQUENCE AND AT A SELECTED POINT DURING THE PERIODS WHEN FORWARD VOLTAGE IS APPLIED THERETO FROM SAID SOURCE, SAID MEANS COMPRISING; (B) A FIRING CONTROL CIRCUIT FOR EACH OF SAID THREE BRANCHES OF THE NETWORK, EACH SAID FIRING CONTROL CIRCUIT COMPRISING; (C) MEANS COMPRISNG A CAPACITOR FOR DEVELOPING A LINEARLY INCREASING VOLTAGE FOR EACH SAID FORWARD VOLTAGE PERIOD OF THE CONTROLLED-RECTIFIERS IN THE ASSOCIATED BRANCH; (D) TRIGGERING MEANS RESPONSIVE TO SAID LINEARLY IN CREASING VOLTAGE WHEN IT REACHES A PREDETERMINED VALUE FOR INITIATING DISCHARGE OF SAID CAPACITOR THERETHROUGH; (E) MEANS COMPRISING A CONTROLLED-RECTIFIER RESPONSIVE TO SAID DISCHARGE CURRENT FOR CAUSING VERY QUICK DISCHARGE OF SAID CAPACITOR THERETHROUGH; (F) AND A PULSE TRANSFORMER RESPONSIVE TO THE VERY QUICK DISCHARGE CURRENT FOR APPLYING FIRING VOLTAGE PULSES OF VERY SHORT DURATION TO THE CONTROLLEDRECIFIERS IN THE ASSOCIATED BRANCH OF THE NETWORK.